Method for preparing N{HD 1{B -(2{40 -furanidyl)-and N{HD 1{B -2(2{40 -pyranidyl) uracils

ABSTRACT

A method for preparing N1-(2&#39;&#39;-furanidyl)- and N1-(2&#39;&#39;-pyranidyl) uracils having the general formula   WHERE R is hydrogen, methyl, trihalomethyl, or a halogen, X is CH or N, and n is 1 or 2, characterized in that 2,4-bis (trimethylsilyl) derivatives of uracils having the general formula   WHERE R is hydrogen, methyl, trihalomethyl or a halogen, X is CH or N, are treated with a 2-substituted cyclic ester having the general formula   WHERE R1 is acyl or alkyl, and n is 1 or 2, in the presence of Friedel-Crafts catalysts in a medium of an organic solvent inactive with respect to the said starting components.

United States 1 Patent [1 1 Ciller et al.

[4 1 Oct. 14, 1975 METHOD FOR PREPARING N,-(2-FURANIDYL)-AND N,-(2-PYRANIDYL) URACILS [22] Filed: June 1, 1973 [21] Appl. No.: 366,215

[30] Foreign Application Priority Data Nov. 20, 1972 U.S.S.R ..l848519 [52] US. Cl 260/248 AS; 260/260; 424/249;

424/251 [51] Int. Cl. C07d 55/10; C07d 51/36 [58] Field of Search 260/260, 248 AS [56] References Cited UNITEDSTATES PATENTS 3,352,849 ll/1967 Shen et al, 260/248 X Primary Examiner-John M. Ford Attorney, Agent, or FirmWaters, Schwartz & Nissen [57] ABSTRACT A method for preparing N -(2'-furanidyl)- and N,-(2- pyranidyl) uracils having the general formula HA/ P -LL/h where R is hydrogen, methyl, trihalomethyl, or a halogen, X is CH or N, and n is 1 or 2, characterized in that 2,4-bis (trimethylsilyl) derivatives of uracils having the general formula Si (CH 3 (CH SiO k where R is hydrogen, methyl, trihalomethyl or a halogen, X is CH or N, are treated with a 2-substituted cyclic ester having the general formula where R is acyl or alkyl, and n is l or 2, in the presence of Friedel-Crafts catalysts in a medium of an organic solvent inactive with respect to the said starting components.

4 Clairns, N0 Drawings METHOD FOR PREPARING N,-(2-FURANIDYL).-AND N,-2(2'-PYRANIDYL) URACILS' The invention relates to a method for preparing uracils, and more particularly it relates to a method for 5 preparing N,-( 2'-furanidyl)- and N,-( 2-pyranidyl) uracils having the general formula i (CH n physiological activity and are used in medicine. For example, N -(2-furanidyl)-5-fluorouracil is an active principle of an anti-tumour preparation known Ftorafur. This preparation is widely used for treating cancer of the gastro-intestinal tract and of the mammary gland.

Known in the prior art is a method for preparing these compounds, consisting in the action of 2,4-bis(- trimethylsilyl) derivatives of uracil on 2 chlorofuranidine or 2-chloropyranidine (C. A. Giller, R. A. Zhuk, M. Y. Lidak, A. A. Zinderman, British Pat. No. 1,168,391).

The disadvantages of this method are the instability of 2-chlorofuranidine and 2-chloropyranidine, and the low temperatures of the process, namely, from 20C to l()C.

The object of this invention is to work out a process for synthesizing N,-(2'-furanidyl)- and N,-(2'- pyranidyl) uracils convenient for application on an industrial scale.

These and other objects of the invention have been attained in a method for preparing N,-(2-furanidyl)- and N -(2'-pyrinidyl) uracils having the general formula 0 where R, X areas specified above, are reacted with a 2-substituted cyclic ester having the general formula C(CE O where R, is acyl or alkyl, and n is from 1 to 2, in the presence, of Friedel-C rafts catalysts in a medium which is an organic solvent inactive with respect to the starting components.

The interaction between the said components can be expressed by the following scheme where R, X, R, and n are as specified above.

The use of 2-substituted cyclic ethers, having the above-specified formula, as a starting component, has enabled the preparation of N,-(2'-furanidyl)- and N. (Z-pyranidyl) uracils of good quality and in higher yields lO-l5 per cent higher compared with the known process), the process for their manufacture and isolation being significantly simplified.

The method for preparing the said uracils consists in the following.

To a solution of 2,4-bis(trimethylsilyl) derivative of uracil having the above-specified general formula in an organic solvent are, added a 2-substituted cyclic ether of the above-specified general formula and, slowly dropwise, and with stirring, a solution of the said catalyst in an organic solvent. The reaction continues for 1-2 hours at room temperature, or at an elevated temperature, (depending on the starting components), and at normal atmospheric pressure. The solvent is then distilled in vacuo from the reaction mixture, and ethyl alcohol is added to the residue to remove the remaining trimethylsilyl group. The mixture is stirred for two hours and the precipitate of N -(2'-fi1ranidyl)- or N (2'-pyranidyl) uracil is allowed to settle, separated on a filter and washed with a small quantity of cool ethyl alcohol. The preparation is finally isolated by re-crystallization from chloroform.

SnCl TiCl ZnCI- AlCl SiCl BF .(C H O and. other Friedel-Crafts catalysts are used to catalyze the process.

l,2-dichloroethane, chloroform, methylene chloride, benzene, acetonitrile dimethylformamide and other organic solvents can be used as solvents for the process according to the invention.

The catalyst that should preferably be used in the process is SnCl and the preferable organic solvent is methylene chloride or l,2-dichloroethane.

EXAMPLE 1 N 2-furanidyl )-methyluracil Into a round-bottomed flask provided with a mechanical stirrer, a' thermometer, a dropping'funnel and a calcium chloride tube are, placed 8.1 g (0.03 mole) of 2,4- bis(trimethylsilyl)-5-methyluracil. 5.1 g (0.039 mole) of 2-acetoxyfuranidine and 30 ml of anhydrous dichlo roethane. A solution of 5.2 g (2.3 ml, 0.02 mole) of tin tetrachloride in ml of dichloroethane is added with stirring, and the reaction mixture is kept for two hours at room temperature. The solvent is then distilled in vacuo and 18 ml of ethyl alcohol are addcddropwise. The mixture is stirred for minutes at room temperature, and the precipitate is then separated. The resultant product is N,-(2'-furanidyl)-5-methyluracil in the quantity of 5.0 g, which is 85 per cent of theory, as calculated with reference to 2,4-bis(trimethylsilyl)-5- methyluracil. This is a white crystalline substance melting at 182 184C (chloroform).

C,,H, O;,N Found, in per cent: C, 55.31; H, 6.28; N, 14.18.

Calculated, in per cent: C, 55.0.9; H, 6.17; N, 14.28.

The procedurein the Examples that follow is the same as described in Example 1.

4 EXAMPLE 2 N,-( 2'-furanidyl )-5-fluorouracil EXAMPLE 3 N1-( 2 '-furanidyl )-5-bromouracil 10.1 g 0.03 mole) 8f 2,4-bis(trimethylsilyl)-5- vbrornouracil are reacted with 5.1 g (4.7 ml, 0.039

mole) of 2-acetoxyfuranidine in a medium of chloroform in the presence of 5.2 g (2.3 ml, 0.02 mole) of tin tetrachloride for 2 hours at a temperature from to C to yield 5.0 g (64 per cent of theory) of N -(2'- furanidyl)-5-bromouracil, which is a white crystalline substance melting at 208210C (decomposition), (chloroform). v

C H O N Br: Found, in per cent: C, 36.28; H 3.63; N, 1 1,01;

Calculated, in per cent: C, 36.76; H, 3.44; N, 10,73.

EXAMPLE 4 N 2-furanidyl )-5-trifluoromethyluracil methylene chloride in the presence of 5.2g (2.3 ml, 0.02 mole) of tin tetrachloride for 2 hours at room tem perature to yield 6.0 g per cent of theory) of N 2'-furanidyl)-5-trifluoromethyluracil, which is a white crystalline substance melting at 206208C (chloroform). 1 l

C H N O F Found, in per cent: C, 43.18; H, 3.51; N, 1 1.00.

Calculated, in per cent: C, 43.21; H, 3.63; N, 11.20.

EXAMPLE 5 N 2 '-furanidyl )-6-azauracil 7.7 g (0.03 mole) of 2,4-bis(trimethylsilyl)-6- azauracil are reacted with 5.1 g (4.7 ml, 0.039 mole) of 2-acetoxyfuranidine in a medium of dichloroethane in the presence of 5.2 g (2.3 ml',0.02 mole) of tin tetrachloride for 2 hours at room temperature to yield 3.4 g (62 per cent of theory) of N,-(2-furanidyl)-6- azauracil, which is a white crystalline substance, melting at 121123C (carbon tetrachloride).

C H N O Found, in per cent: C, 45.82; H, 4.78; N,

Calculated, in per cent: C, 45.90; H, 4.95; N, 22.94.

EXAMPLE 6 N 2 -pyranidyl )-5-fluorouracil 8.2 g (0.03 mole) of 2,4-bis(trimethylsilyl)-5- fluorouracil are reacted with 4.5 g (4.1 ml, 0.039 mole) of 2-methoxytetrahydropyrane in a medium of chloroform in the presence of 5.2 g (2.3 ml, 0.02 mole) of tin tetrachloride for 2 hours at a temperature of 35 to 40C to yield 3.5 g (55 per cent of theory) of N,-(2- pyranidyl)-5-fluorouracil, which is a white crystalline substance melting at 172 173C (chloroform).

C H,,N O -,F: Found, in per cent: C, 50.64; H, 5.44; N, 13.13. 1

Calculated in per cent: C, 50.46; H, 5.14; N, 13.08.

EXAMPLE 7 N 2-furanidyl )-uraci1 7.7 g (0.03 mole) of 2,4-bis(trimethylsilyl)-6- azauracil are reacted with 5.1 g (4.7 ml, 0.039 mole) of 2-acetoxyfuranidine in a medium of dichloroethane in the presence of 3.4 g (2.3 ml, 0.02 mole) of silicon tetrachloride for 2 hours at room temperature to yield 1.9 g (35 per cent of theory) of N -(2'-furanidyl)- uracil, which is a white crystalline substance, melting at 102l04C (ethanol).

C H N Q Found, in per cent: C, 52.17; H, 5.60; N, 15.68.

Calculated, in per cent: C, 52.74; H, 5.53; N, 15.38.

EXAMPLE 8 N 2"-pyranidyl )-5 -bromo-6-azauracil 10.1 g (0.03 mole) of 2,4-bis(trimethylsilyl)-5- bromo-6-azauracil are reacted with 7.8 g (7.4 ml, 0.06 mole) of 2-ethoxy pyranidine in a medium of dichloroethane in the presence of 4.1 g (0.03 mole) of zinc chloride for two hours at room temperature to yield 2.5 g (30 per cent of theory) of N -(2'-pyranidyl)-5- bromo-6-azauracil, which is a white crystalline substance, melting at l97C'(chloroform).

C H N O Br: Found, in per cent: C, 34.69; H, 3.85; N, 14.90.

Calculated, in per cent: C, 34.80; H, 3.65; N, 15.22.

What is claimed is:

l. A method for the production of a compound of the formula orda n),

where R is selected from the group consisting of hydrowhere R is selected from the group consisting of acetyl and alkyl, and n is from 1 to 2, in the presence of a Friedel-Crafts catalyst in a medium of an organic solvent inactive with respect to the said starting components.

2. A method according to claim I, in which the molar ratio of the 2,4-bis(trimethylsilyl) derivative to the 2- substituted cyclic ether and to the catalysts is selected within the range of l:l-2:O.52.

3. A method according to claim 1, in which the solvent is selected from the group consisting of dichloroethane, chloroform, methylene chloride, benzene and dimethyl formamide.

4. A method according to claim 1, in which the catalyst is selected from the group consisting of SnCl TiCl ZnCl AlCl SiCl BF .(C H O. 

1. A METHOD FOR THE PRODUCTION OF A COMPOUND OF THE FORMULA
 2. A method according to claim 1, in which the molar ratio of the 2,4-bis(trimethylsilyl) derivative to the 2-substituted cyclic ether and to the catalysts is selected within the range of 1:1- 2:0.5-2.
 3. A method according to claim 1, in which the solvent is selected from the group consisting of dichloroethane, chloroform, methylene chloride, benzene and dimethyl formamide.
 4. A method according to claim 1, in which the catalyst is selected from the group consisting of SnCl4, TiCl4, ZnCl2, AlCl3, SiCl4, BF3.(C2H5)2O. 